Electronic circuitry

ABSTRACT

Timing signal generation and distribution are combined in operation of a signal path exhibiting endless electromagnetic continuity affording signal phase inversion and having associated regenerative active means. Two-or more-phases of substantially square-wave bipolar signals arise directly in travelling wave transmission-line embodiments compatible with semiconductor fabrication including CMOS. Coordination by attainable frequency synchronism with phase coherence for several such oscillating signal paths has intra-IC inter-IC and printed circuit board impact, as does two-way simultaneous data transfer.

FIELD OF INVENTION

[0001] The invention relates to electronic circuitry concerning timingsignals and their production and distribution; oscillators as sources ofsuch as timing signals; and communications according to timing signals.

BACKGROUND TO INVENTION

[0002] Digital electronic data processing circuitry and systems requiretiming signals to synchronise data processing activities. Customarily,such timing signals include a master timing signal from which othertiming signals can be derived. Such a master timing signal is commonlyreferred to as a ‘clock’ signal. It is often desirable to have a clocksignal that is available in more than one phase.

[0003] An example of a two-phase clock signal is where available clocksignals have a phase difference of 180-degrees as often used for dynamiclogic and shift register circuitry. An example of a four-phase clocksignal is where available clock signals have successive phasedifferences of 90-degrees. Semiconductor integrated circuits (ICs orchips) are typical host environments, often very large scale (VLSI)chips as for microprocessors or memories.

[0004] Historically, modest operating clock frequencies up to about 50MHz were satisfied by use as off-chip quartz crystal clock oscillatorwith simple point-to-point on-chip clock signal distribution. Nowadays,at much higher operating frequencies, typically aiming for 300 MHz to 1GHz, inherent on-chip distribution problems associated with clock signalreflection and skew have become highly significant as binary signalwidths/durations are no longer so much shorter than clock signal pulses.Natural progression of IC designs is for chips to become physicallybigger and functionally more complex, which compounds these problems.

[0005] Clock signal generation is presently typically by frequencymultiplication from off-chip crystal clock oscillators using on-chipphase locked loop (PLL) control circuitry which occupies valuable chiparea, consumes considerable power, and experiences problems with signalreflections, capacitive loading and power dissipation that effectivelylimit maximum operating frequency. Related clock signal distributionusually involves tree-like arrangement of operational circuitry withchains of clock signal boosting buffers at intervals. Even so,variability of semiconductor process parameters, including in thebuffers, leads to undesirable and unpredictable phase delays (skew) atdifferent positions on the chip, thus can adversely affect reliablesynchronous operation and communication even for neighbouring areas of achip. As a result, ICs often have to be rated and run at lower thanmaximum designed-for clock rates. Indeed, IC manufacturers are evenreversing long-standing trends by use of smaller chip sizes for latestICs.

[0006] The development of ever more comprehensive ‘systems-on-silicon’chips is being hampered by lack of viable provisions for reliablyclocking large area high-density chips. It is noteworthy that clockrates tend to be limited to less than about 1 GigaHertz despite such asMosfet IC transistor features being capable of switching at 25 GigaHertzor more.

[0007] This invention arises basically from looking for some alternativeapproach that at least reduces areal and/or power demands of on-chip PLLprovisions, if possible further addresses and to some useful extentresolves clock signal distribution problems.

SUMMARY OF INVENTION

[0008] One broad view or aspect of this invention resides in the conceptand realisation of method and means for effectively integrating orsynergistically combining distribution of repeating pulse or cyclicsignals with active means for producing and maintaining those signals. Acomposite electromagnetic/semiconductor structure is facilitated thatsimultaneously generates and distributes timing signals, including amaster clock. A suitable said signal path exhibits endlesselectromagnetic continuity affording signal phase inversion of anelectromagnetic wave type signal, conveniently with path-associatedregenerative means.

[0009] A successful inventive rationale aspect hereof has been evolvedin which time constant for repeating pulse or cyclic signals is relatedto and effectively defined by electrical length of said signal path inthe signal distribution means. A travelling electromagnetic waverecirculating endlessly electromagnetically continuous said signal pathis preferred, when its traverse time of the signal path determines saidtime constant.

[0010] Interestingly and quite surprisingly, this has been found to beconducive to particular inventive direct production of pulse-like cyclicsignals inherently having fast rise and fall characteristics, i.e.already “square” as produced, rather than requiring resort to “squaring”action on a basic inherently substantially sinusoidal signal as hithertoconventional. Indeed, such inventive electrical length/signal traversetime-constant-defining rationale hereof leads conveniently andadvantageously to said electrical length or one said signal traverseeffectively first defining one unipolar half-cycle signal excursion andnext, or at next said signal traverse, effectively completing definitionof a full bipolar cycle comprising two opposite half-cycle excursions.Said electrical length thus corresponds to 180-degrees for each of twosuccessive pulse excursions for such full bipolar cycle.

[0011] Specific inventive aspects hereof to achieve such rationale areviewed as involving signals of a travelling wave nature with the signaldistribution path involved having a suitably propagating naturetherefor, typically of endless transmission-line form, further withtransposing effect and inverting action associated with re-circulationsof desired signals.

[0012] In one specific inventive aspect hereof, desired repeating cyclicsignals involve re-circulatory travelling wave propagation meanseffectively affording rotation thereabout by a desired travelling waveand setting duration of each signal excursion, with active regenerativemeans that can be of switching and amplifying nature, convenientlybidirectional inverting amplifier, supplying energy requirements andsetting relatively short rise and fall at ends of each signal excursion.

[0013] Suitable travelling wave propagation means with desiredtransposing effect relative to active inverting means is exemplified, asseen by the traversing travelling wave, by physical width twisted alongits length to connect opposite sides to input and output of theinverting means, say as though a Moebius band or ribbon. Indeed, anintegrated circuit made on a flexible substrate could be of elongateform with said path following its length and its ends interconnected asa Moebius band or ribbon, even with functional circuitry blocks toeither or both sides of or straddling its travelling wave propagationfeature. At least then, integration of inverting and travelling wavepropagating features of cyclic signal means hereof could be to theextent of up to all its length being of continuous semiconductorinverter nature, at least using CMOS technology.

[0014] However, for planar implementation of travelling wave propagationmeans, a typical transmission-line form uses spaced path-followingconducting features, aforesaid Moebius twist effect being afforded byway of no more than a mutually insulated cross-over of those spacedconducting features. An alternative would be use of a transmission-lineinverting transformer in or associated with otherwise transmission-lineform of the travelling propagation means.

[0015] An inventive aspect of exemplary implementation hereof usesspaced conductive features as trace formations each having substantiallythe same length and being transposed on the way between output and inputof at least one inverter feature connected to, preferably between, thoseconductive traces. In practice, at least where the inverter feature isof extent less than about 1% along the conductive features, there willpreferably be plural inverter features spaced along the conductivefeatures or traces—unless this invention is adapted to operation as astanding wave oscillator.

[0016] Preferred inverter means is of bidirectional nature, such as apair of opposite inverters side-by-side or back-to-back; and suchprovision facilitates direct simultaneous production of similar orsubstantially identical anti-phase cyclic signal components.

[0017] Particularly interesting and advantageous results available fromthis invention include timing signal provision with extremely low powerconsumption that can effectively be limited to transmission-line andinverter action losses, i.e. to near-negligible topping-up via theinverter provision(s), and take-off to operational circuitry is readilymade, e.g. by way of light bidirectional connection paths of passiveresistive and/or capacitive and/or inductive or transmission-linenature, or unidirectional say using diodes or inverters, etc as will bedescribed in more detail.

[0018] Another such available result is that, at least in principle andabsent fabrication imperfections, cyclic signal provision hereof has noinnate preference for either direction or rotation of travelling wavepropagation, though either may be predisposed or imposed by such asprescribed spacings or other differences between or within invertermeans.

[0019] Inventive proposals and aspects hereof as to pulse generators andoscillators as such include transmission-line structures usingconductive metal and insulating dielectric layers in a manner compatiblewith IC production generally and particularly together with regenerativecircuitry associated with the transmission-line as such, typically andconveniently formed below and connected by vias; required insulatedcross-overs or spaced transmission-line transformer parts are likewisereadily formed including such as via jump connections for thecross-overs; and resulting advantageously DC unstable interconnection ofterminals of such as bidirectional inverters as the regenerative means;synchronous detection and bridge rectifier action of preferredbidirectional inverters; reinforcing sequential action of suchbidirectional inverters including recycling electrical energy relativeto supplies; etc.

[0020] Moreover, there are inventive aspects ininterconnection/intercoupling of timing signal generating anddistribution circuitry hereof, whether by direct connection or bysharing magnetic and/or electrical fields; and doing so on aself-synchronising basis with extension to different frequenciesparticularly in odd-harmonic relationship. Intercoupling andcoordinating between ICs as such and further with transferring data alsohave important innovative and inventive merit.

[0021] Other aspects and features of the present invention arise laterin this Description, and/or are as set out in independent and dependentclaims wording of which is to be taken as incorporated here too.

BRIEF DESCRIPTION OF DRAWINGS

[0022] Specific exemplary implementation for the invention is nowdescribed and shown by reference to the accompanying diagrammaticdrawings, in which

[0023]FIG. 1 is an outline diagram for a transmission-line structurehereof;

[0024]FIG. 2 shows a Moebius strip;

[0025]FIG. 3 is an outline circuit diagram for a travelling waveoscillator hereof;

[0026]FIG. 4 is another outline circuit diagram for a travelling waveoscillator hereof;

[0027]FIGS. 5a and 5 b are equivalent circuits for distributedelectrical models of a portion of a transmission-line hereof;

[0028]FIG. 6a shows idealised graphs for respective differential outputwaveforms hereof;

[0029]FIG. 6b illustrates relationship between propagation delay,electrical length and physical length of a transmission-line hereof;

[0030] FIGS. 7(i)-7(ix) are idealised graphs illustrating the phase ofsignal waveforms hereof;

[0031]FIGS. 8a-8 c illustrate instantaneous phasing of one waveform in atransmission-line oscillator hereof;

[0032]FIG. 9 is a cross sectional view of part of a transmission-line onan IC;

[0033]FIGS. 10a and 10 b are outline circuit and idealised graphs for astanding wave version;

[0034]FIG. 11 is a scrap outline of a transmission-line with invertingtransformer;

[0035]FIG. 12 shows a pair of back-to-back inverters connected acrosspart of a transmission-line;

[0036]FIGS. 13a and 13 b are outline and equivalent circuit diagrams ofCMOS back-to-back inverters;

[0037]FIG. 14a details capacitive elements of a transmission-linetogether with CMOS transistors;

[0038]FIG. 14b is on an equivalent circuit diagram for FIG. 14a;

[0039]FIG. 15 shows capacitive stub connections to a transmission-line;

[0040]FIG. 16 shows one connection for self-synchronisingtransmission-line oscillators;

[0041]FIGS. 17a-17 c show other connections for self-synchronisingtransmission-line oscillators;

[0042]FIG. 18 is a diagrammatic equivalent representation for FIG. 13a;

[0043]FIGS. 19a and 19 b show connection of four transmission-lineoscillators;

[0044]FIGS. 20 and 21 show magnetically coupled self-synchronisedtransmission-line oscillators;

[0045]FIG. 22 shows three magnetically couple self-synchronisedtransmission-line oscillators;

[0046]FIG. 23 shows connection of self-synchronising transmission-linesoscillators of different frequencies;

[0047]FIG. 24 shows an example of a clock distribution network for amonolithic IC;

[0048]FIG. 25 shows 3D implementation for timing systems hereof;

[0049]FIGS. 26a and 26 b show examples of dual phase tap-off points;

[0050]FIG. 27 shows three concentrically arranged transmission-lineoscillators;

[0051]FIGS. 28a and 28 b show a transmission-line having a cross-loopconnection;

[0052]FIG. 29a shows a transmission-line configuration for four-phasesignals;

[0053]FIG. 29b shows idealised resulting four-phase signal waveforms;

[0054]FIG. 30 shows an open-ended transmission-line connection;

[0055]FIG. 31 concerns co-ordinating frequency and phase for two IC's;

[0056]FIG. 32a concerns data transfer for frequency and phaseco-ordinated IC's;

[0057]FIGS. 32b-32 e concern data latches for the system of FIG. 32a;

[0058]FIG. 33 shows digitally selectable shunt capacitors of Mosfettype; and

[0059]FIG. 34 shows capacitive loading and routing data and/or poweracross a transmission-line.

DETAILED DESCRIPTION FOR ILLUSTRATED EMBODIMENTS

[0060] Known transmission-lines broadly fall into two categories in thatthey are either open-ended or specifically terminated either partiallyor fully. Transmission-lines as proposed herein are different in beingneither terminated nor open-ended. They are not even unterminated assuch term might be understood hitherto; and, as unterminated herein, areseen as constituting a structural aspect of invention, including byreason of affording a signal path exhibiting endless electromagneticcontinuity.

[0061]FIG. 1 shows such a transmission-line 15 as a structure that isfurther seen as physically endless, specifically comprising a singlecontinuous “originating” conductor formation 17 shown forming twoappropriately spaced generally parallel traces as loops 15 a, 15 b witha cross-over at 19 that does not involve any local electrical connectionof the conductor 17. Herein, the length of the originating conductor 17is taken as S, and corresponds to two ‘laps’ of the transmission-line 15as defined between the spaced loop traces 15 a, 15 b and through thecross-over 19.

[0062] This structure of the transmission-line 15 has a planarequivalence to a Moebius strip, see FIG. 2, where an endless strip witha single twist through 180° has the remarkable topology of effectivelyconverting a two-sided and two-edged, but twisted and ends-joined,originating strip to have only one side and one edge, see arrowsendlessly tracking the centre line of the strip. From any position alongthe strip, return will be with originally left- and right-hand edgesreversed, inverted or transposed. The same would be true for any oddnumber of such twists along the length of the strip. Such a strip ofconductive material would perform as required for signal paths ofembodiments of this invention, and constitutes another structural aspectof invention. A flexible substrate would allow implementing a trueMobius strip transmission-line structure, i.e. with graduality of twistthat could be advantageous compared with planar equivalent cross-over19. A flexible printed circuit board so formed and with its ICs mountedis seen as a feasible proposition.

[0063]FIG. 3 is a circuit diagram for a pulse generator, actually anoscillator, using the transmission-line 15 of FIG. 1, specificallyfurther having plural spaced regenerative active means conveniently asbi-directional inverting switching/amplifying circuitry 21 connectedbetween the conductive loop traces 15 a, 15 b. The circuitry 21 isfurther illustrated in this particular embodiment as comprising twoinverters 23 a, 23 b that are connected back-to-back. Alternativesregenerative means that rely on negative resistance, negativecapacitance or are otherwise suitably non-linear, and regenerative (suchas Gunn diodes) or are of transmission-line nature. It is preferred thatthe circuitry 21 is plural and distributed along the transmission-line15, further preferably evenly, or substantially evenly; also in largenumbers say up to 100 or more, further preferably as many and each assmall as reasonably practical.

[0064] Inverters 23 a, 23 b of each switching amplifier 21 will have theusual operative connections to relatively positive and negative supplyrails, usually V+ and GND, respectively. Respective input/outputterminals of each circuit 21 are shown connected to thetransmission-line 15 between the loops 15 a, 15 b at substantiallymaximum spacing apart along the effectively single conductor 17, thuseach at substantially halfway around the transmission-line 15 relativeto the other.

[0065]FIG. 4 is another circuit diagram for an oscillator using atransmission-line structure hereof, but with three cross-overs 19 a, 19b and 19 c, thus the same Moebius strip-likereversing/inverting/transposing property as applies in FIG. 3.

[0066] The rectangular and circular shapes shown for thetransmission-line 15 are for convenience of illustration. They can beany shape, including geometrically irregular, so long as they have alength appropriate to the desired operating frequency, i.e. so that asignal leaving an amplifier 21 arrives back inverted after a full ‘lap’of the transmission-line 15, i.e. effectively the spacing between theloops 15 a,b plus the crossover 19, traversed in a time Tp effectivelydefining a pulse width or half-cycle oscillation time of the operatingfrequency.

[0067] Advantages of evenly distributing the amplifiers 21 along thetransmission-line 15 are twofold. Firstly, spreading stray capacitanceeffectively lumped at associated amplifiers 21 for better and easierabsorbing into the transmission-line characteristic impedance Zo thusreducing and signal reflection effects and improving poor waveshapedefinition. Secondly, the signal amplitude determined by the supplyvoltages V+ and GND will be more substantially constant over the entiretransmission-line 15 better to compensate for losses associated with thetransmission-lines dielectric and conductor materials. A continuousclosed-loop transmission-line 15 with regenerative switching means 21substantially evenly distributed and connected can closely resemble asubstantially uniform structure that appears the same at any point. Agood rule is for elementary capacitance and inductance (Ce and Le)associated with each regenerative switching means and forming a resonantshunt tank LC circuit to have a resonant frequency of ½*pi*root(Le*Ce)that is greater than the self-sustaining oscillating frequency F (F3, F5etc.) of the transmission-line 15.

[0068]FIG. 5a is a distributed electrical equivalent circuit or model ofa portion of a transmission-line 15 hereof. It shows alternatedistributed resistive (R) and inductive (L) elements connected inseries, i.e. R₀ connected in series with L₁ in turn connected in serieswith R₂ and so on for a portion of loop 15 a, and registering L₀connected in series with R₁ in turn connected in series with L₂ and soon for the adjacent portion of loop 15 b; and distributed capacitiveelements C₀ and C₁ shown connected in parallel across thetransmission-line 15 thus to the loops 15 a and 15 b between theresistive/inductive elements R₀/L₁ and the inductive/resistive elementsL₀/R₁, respectively for C₀ and between the inductive/resistive elementsL₁/R₂ and the resistive/inductive elements R₁/L₂, respectively for C₁:where the identities R0=R1=R2, L1=L2=L3 and C0=C1 substantially hold andthe illustrated distributed RLC model extends over the whole length ofthe transmission-line 15. Although not shown, there will actually be aparasitic resistive element in parallel with each capacitive element C,specifically its dielectric material.

[0069]FIG. 5b is a further simplified alternative distributed electricalequivalent circuit or model that ignores resistance, see replacement ofthose of FIG. 5a by further distribution of inductive elements in seriesat half (L/2) their value (L) in FIG. 5a. This model is useful forunderstanding basic principles of operation of transmission-linesembodying the invention.

[0070] During a ‘start-up’ phase, i.e. after power is first applied tothe amplifiers 21, oscillation will get initiated from amplification ofinherent noise within the amplifiers 21, thus begin substantiallychaotically though it will quickly settle to oscillation at afundamental frequency F, typically within nano-seconds. For eachamplifier 21, respective signals from its inverters 23 a and 23 b arriveback inverted after experiencing a propagation delay Tp around thetransmission-line 15. This propagation delay Tp is a function of theinductive and capacitive parameters of the transmission-line 15; which,as expressed in henrys per meter (L) and in farads per meter (C) toinclude all capacitive loading of the transmission-line, lead to acharacteristic impedance Zo=SQR (L/C) and a line traverse or propagationor phase velocity Pv=1/SQR(L/C). Reinforcement, i.e. selectiveamplification, of those frequencies for which the delay Tp is an integersub-divisor of a half-cycle time gives rise to the dominant lowestfrequency, i.e. the fundamental frequency F=1/(2*Tp), for which thesub-divisor condition is satisfied. All other integer multiples of thisfrequency also satisfy this sub-divisor condition, but gain of theamplifiers 21 ‘falls off’, i.e. decreases, for higher frequencies, sothe transmission-line 15 will quickly settle to fundamental oscillationat the frequency F.

[0071] The transmission-line 15 has endless electromagnetic continuity,which, along with fast switching times of preferred transistors in theinverters 23 a and 23 b, leads to a strongly square wave-form containingodd harmonics of the fundamental frequency F in effectively reinforcedoscillation. At the fundamental oscillating frequency F, including theodd harmonic frequencies, the terminals of the amplifiers 21 appearsubstantially unloaded, due to the transmission-line 15 being‘closed-loop’ without any form of termination, which results verydesirably in low power dissipation and low drive requirements. Theinductance and capacitance per unit length of the transmission-line 15can be altered independently, as can also be desirable and advantageous.

[0072]FIG. 6a shows idealised waveforms for a switching amplifier 21with inverters 23 a and 23 b. Component oscillation waveforms Φ1, Φ2appear at the input/output terminals of that amplifier 21 shortly afterthe ‘start-up’ phase, and continue during normal operation. Thesewaveforms Φ1 and Φ2 are substantially square and differential, i.e.two-phase inverse in being 180 degrees out-of-phase. These differentialwaveforms Φ1 and Φ2 cross substantially at the mid-point (V+/2) of themaximum signal amplitude (V+). This mid point (V+/2) can be consideredas a ‘null’ point since the instant that both the waveforms Φ1 and Φ2are at the same potential, there is no displacement current flow presentin nor any differential voltage between the conductive loop traces 15 aand 15 b. For the preferred recirculating travelling wave aspect of thisinvention, this null point effectively sweeps round the transmissionline 15 with very fast rise and fall times and a very ‘clean’square-wave form definition. This null point is also effectively areference voltage for opposite excursions of a full cycle bipolar clocksignal.

[0073] For the transmission-line 15, it is convenient to considercomplete laps as traversed by a travelling wave, and also total length Sof the originating conductive trace 17, both in terms of ‘electricallength’. FIG. 6b shows relationships between the propagation delay ortraverse time (Tp), electrical length in degrees, and physical length(S) of originating conductive line/trace 17. For each of theout-of-phase waveforms Φ1 and Φ2, and as seen by a travelling waverepeatedly traversing the transmission-line 15, each substantiallysquare wave excursion corresponds to one complete lap, i.e. one traversetime Tp, and successive opposite wave excursions require two consecutivelaps, i.e. two traverse times (2×Tp). One lap of the transmission-line15 thus has an ‘electrical length’ of 180 degrees, and two laps arerequired for a full 0°-360° bipolar signal cycle, i.e. corresponding tothe full lengths of the originating conductor 17.

[0074] By way of example, an electrical length of 180° corresponding toone lap and ½ wavelength at 1 GHz could be formed from a 50 mmtransmission-line having a phase velocity (Pv) that is 30% that of thespeed of light (c), i.e. Pv=0.3*c, or 5 mm where Pv=0.03*c, or 166 mm infree space, i.e. where Pv=1*c.

[0075] FIGS. 7(i)-7(ix) show waveforms Φ1, Φ2 through a full cycle tostart of the next cycle, specifically at eight equal electrical-lengthspacings of 45 degrees between sample positions along the conductor lineor trace 17. Phase labellings are relative to FIG. 7(i) which can beanywhere along the trace 17, i.e. twice round the transmission line 15,as such, and 0/360-degrees for rise/fall of the Φ1, Φ2 waveforms 15 isarbitrarily marked. Taking FIG. 7(i) as time t0, FIG. 7(ii) shows thewaveforms Φ1, Φ2 at time t0+(0.25Tp) after one-eighth (0.125S) traverseof total length S of the line 17, thus traverse of one-quarter of thetransmission line 15, and 45-degrees of electrical length. Timest0+(0.5Tp), t0+(0.75Tp), t0+(0.75Tp) . . . t0+(2Tp); traverses 0.25S,0.375S, 0.5S . . . 1.0S and 90, 135, 180 . . . 360-degrees shouldreadily be seen self-evidently to apply to FIGS. 7(iii)-(ix),respectively.

[0076]FIGS. 8a and 8 b show snap-shots of excursion polarity (showncircled), displacement current flow (shown by light on-trace arrows),and instantaneous phasing from an arbitrary 0/360-degree position on theelectromagnetically endless transmission line 15 covering two lapsthereof (thus the full length the continuous originating conductor 17).Only one differential travelling electromagnetic (EM) waveform (say Φ1)of FIG. 7 is shown, but for rotation propagation around thetransmission-line 15 in either of opposite directions, i.e. clockwise orcounter-clockwise. The other waveform (Φ2) will, of course be 180° outof phase with the illustrated waveform (Φ1). The actual direction ofrotation of the EM wave will be given by Poyntings' vector, i.e. thecross product of the electric and magnetic vectors. The crossover region19 produces no significant perturbation of the signals Φ1 or Φ2 as theEM wave traverses this region 19. In effect, the fast rise/falltransitions travel round the transmission-line at phase velocity Pv, theswitching amplifiers 21 serving to amplify the transitions during firstswitching between supply voltage levels.

[0077] The phases of the waveforms Φ1 and Φ2 can, for atransmission-line 15 hereof, be accurately determined from any arbitraryreference point on the transmission-line 15, thus have strong coherenceand stability of phasing.

[0078] Suitable (indeed preferred in relation to present ICmanufacturing technology and practice) switching amplifiers 21 forbidirectional operation are based on back-to-back Mosfet inverters 23a,b, for which up to well over 1,000 switching inverting amplifier pairscould be provided along typical lengths of transmission-line structureshereof.

[0079] The bidirectional inverting action of the switching amplifiers 21is of synchronous rectification nature. The rise and fall times of thewaveforms Φ1 and Φ2 are very fast indeed compared with hithertoconventional timing signals, being based on electron-transit-time ofpreferred Mosfet transistors of the inverters 23 a,b. Moreover,reinforcement is related to the transmission-line 15 having lowerimpedance than any ‘on’ transistor in inverters of preferredbidirectional switching amplifiers 21, though total paralleled isusefully of the same order. Switching of such inverters means that eachamplifier 21 contributes to the resulting wave polarity by way of asmall energy pulse which, by symmetry, must propagate in bothdirections, the forwardly directed EM wave pulse thus contributing asdesired. The reverse EM wave pulse that travels back to the previouslyswitched amplifier 21 is of the same polarity as already exists there,thus reinforces the pre-existing switched state. Ohmic paths betweenpower supply rails and the transmission line 15 through ‘on’ transistorsof the preferred inverters of amplifiers 21 ensure that energy of suchreverse EM wave pulses is absorbed into those power supply rails V+,GND, i.e. there is useful power conservation.

[0080] It should be appreciated that implementation could be by otherthan CMOS, e.g. by using N-channel pull-ups, P-channel pull-downs,bipolar transistors, negative resistance devices such as Gunn diodes,Mesfet, etc

[0081] Regarding the transmission-lines 15 as such, a suitable mediumreadily applicable to ICs and PCBs and interconnects generally is ascommonly referred to as microstrip or coplanar waveguide or stripline,and well known to be formable lithographically, i.e. by patterning ofresists and etching. Practical dielectrics for an on-ICtransmission-line include silicon dioxide (SiO₂) often referred to asfield oxide, inter-metal dielectrics, and substrate dielectrics (whichcan be used at least for semi-insulating structures, e.g. ofsilicon-on-insulator type).

[0082]FIG. 9 is a cross-section through a portion of one exemplary on-ICtransmission-line formation comprising three metal layers 56, 58 and 60and two dielectric layers 62 and 64. Middle metal layer 58 isillustrated as comprising the two transmission-line loop conductivetraces 15 a and 15 b that are at least nominally parallel. Upper metallayer 60 could be used as an AC ‘ground’ plane and could be connected tothe positive supply voltage V+, lower metal 56 being a ‘ground’ planethat could be connected to the negative supply voltage GND. Thedielectric layers 62 and 64 between the metal transmission-line tracesat 58 and ‘ground’ planes 56 and 58 are typically formed using silicondioxide (SiO2). The full illustrated structure is seen as preferable,though maybe not essential in practice, i.e. as to inclusion of eitheror both of the ‘ground’ planes and the dielectric layers 62, 64. Thephysical spacing 66 between the conductive traces 15 a, 15 b affects thedifferential and common modes of signal propagation, which shouldpreferably have equal, or substantially equal, velocities in order toachieve minimum dispersion of the electromagnetic field from the spacing66. Screening properties improve with use of ‘ground planes’, as doesthe ability for the structure to drive non-symmetrical, i.e. unbalanced,loads applied to the conductive traces 15 a, 15 b.

[0083] Inter-metal dielectric layers on a typical IC CMOS process arethin, typically about 0.7 μm, so microstrip transmission-line featureswith low signal losses must have a low characteristic impedance Zo (ashitherto for unterminated, partially terminated or series terminatedlines acting to reduce signal reflections to a manageable level).Self-sustaining, non-terminated, closed-loop transmission-lines 15hereof inherently have very low power consumption for maintainedtravelling EM wave oscillation as the dielectric and conductor losses tobe overcome are typically low. From FIG. 5b, it will be appreciatedthat, if there were no resistive losses associated with thetransmission-line 15 and amplifiers 21, the transmission-line 15 wouldrequire no more energy than required initially to ‘charge-up’ thetransmission-lines inductive Le and capacitive Ce elements. The EM wavewould continually travel around the transmission-line with all energy inthe transmission-line 15 simply transferred, or recycled between itselectric and magnetic fields, thus capacitive Ce and inductive Leelements. Whilst there must be some resistive losses associated with thetransmission-line 15 and amplifiers 21, see transmission-line resistiveelements R₀-R₂ in FIG. 5a, the resistance is typically low andassociated resistive losses will be also low. There is no penalty hereinfrom for using low-impedance transmission-lines 15, even advantage frombeing less affected by capacitive loading, thus resulting in ‘stiffer’drive to logic gates.

[0084] A crossover 19 can be implemented on an IC using ‘vias’ betweenthe metal layers, preferably with each via only a small fraction oftotal length S of the transmission-line 15.

[0085] A variant is available where a transmission-line 15 hereof hasonly one amplifier 21 connected to the transmission-line, and the EMwave no longer travels around the transmission-line 15 so that astanding wave oscillation results, see FIG. 10a for single amplifier 21and FIG. 10b for differential waveforms. Such amplifier should notextend over more than approximately 5° of the electrical length of thetransmission-line 15. If the single amplifier 21 never goes fully ‘on’or ‘off’ a standing sine wave oscillation will result in thetransmission-line 15, which will have varying amplitude with the samephases at the same positions including two stationary, two ‘nullregions.

[0086] It follows that travelling wave operation will be available usinga few spaced or just one lengthy CMOS bidirectional inverter formation,though plural small inverters will produce smoother faster results.Offsetting formations of the amplifiers 21, even just its input/outputterminals, can predispose a travelling EM wave to one direction oftransmission-line traversal, as could specific starter circuit such asbased on forcing first and slightly later second pulses onto thetransmission-line at different positions, or incorporation of some knownmicrowave directional coupler.

[0087] Inverting transmission-line transformers can be used instead ofthe crossovers (19) and still yield a transmission line having endlesselectromagnetic continuity, see FIG. 11 for scrap detail at 21T.

[0088]FIG. 12 shows a pair of back-to-back inverters 23 a, 23 b withsupply line connectors and indications of distributed inductive (L/2)and capacitive (C) elements of a transmission-line as per FIG. 5b. FIG.13a shows N-channel and P-channel Mosfet implementation of theback-to-back inverters 14 a and 14 b, see out of NMOS and PMOStransistors.

[0089]FIG. 13b shows an equivalent circuit diagram for NMOS (N1, N2) andPMOS (P1, P2) transistors, together with their parasitic capacitances.The gate terminals of transistors P1 and N1 are connected to theconductive trace 15 a and to the drain terminals of transistors P2 andN2. Similarly, the gate terminals of transistors P2 and N2 are connectedto the conductive trace 15 b and to the drain terminals of transistorsP2 and N2. The PMOS gate-source capacitances CgsP1 and CgsP2, the PMOSgate-drain capacitances CgdP1 and CgdP2, and the PMOS drain-source andsubstrate capacitances CdbP1 and CdbP2, also the NMOS gate-sourcecapacitances CgsN1 and CgsN2, the NMOS gate-drain capacitances CgdN1 andCgdN2, and the NMOS drain-source and substrate capacitances CdbN1 andCdbN2 are effectively absorbed into the characteristic impedance Zo ofthe transmission-line, so have much less effect upon transit times ofthe individual NMOS and PMOS transistors. The rise and fall times of thewaveforms Φ1 and Φ2 are thus much faster than for prior circuits.

[0090] For clarity FIGS. 12-14 omit related resistive (R) elements. FIG.23a shows only the capacitive elements (as per FIGS. 12 and 13b) of thetransmission-line 15 together with those of the N/PMOS transistors. FIG.14b illustrates another equivalent circuit diagram for FIG. 14aincluding the transmission-line distributed inductive (L/2) elements andthe effective capacitance Ceff given by:

Ceff=C+CgdN+CgdP+[(CgsN+CdbN+CgsP+CdbP)/4];

[0091] Where:

[0092] CgdN=CgdN1+CgdN2;

[0093] CgdP=CgdP1+CgdP2;

[0094] CgsN=CgsN1+CgsN2;

[0095] CdbN=CdbN1+CdbN2;

[0096] CgsP=CgsP1+CgsP2; and

[0097] CdbP=CdbP1+CdbP2.

[0098] Capacitance loading due to gate, drain, source and substratejunction capacitances are preferably distributed as mentionedpreviously.

[0099] An advantage of having a differential- and common-mode,transmission-line, is that ‘parasitic’ capacitances inherent withinmosfet transistors can be absorbed into the transmission-line impedanceZo, as illustrated in FIGS. 14a and 14 b, and can therefore be used forenergy transfer and storage. The gate-source capacitances (Cgs) of theNMOS and PMOS transistors appear between the signal conductor traces 15a, 15 b and their respective supply voltage rails and can be compensatedfor by removing the appropriate amount of respective capacitance fromconnections of the transmission-line 15 to the supply voltage rails, sayby thinning the conductor traces 15 a, 15 b by an appropriate amount.The gate-drain capacitance (Cgd) of the NMOS and PMOS transistors appearbetween the conductive traces 15 a and 15 b and can be compensated forby proportionally increasing the spacing 66 between the conductivetraces 15 a, 15 b at connections to the NMOS and PMOS transistors of theinverters 23 a/b.

[0100] By way of a non-restrictive example, on a 0.35 micron CMOSprocess, a usable 5 GHz non-overlapping clock signal should result withtransmission-line loop length (S/2) of 9 mm for a phase velocity of 30%of speed-of-light, as determined by capacitive shunt loadingdistribution and dielectric constants, the total length (S), of theconductor 17 thus being 18 mm.

[0101] The substrate junction capacitances (Cdb) of the NMOS and PMOStransistor could be dramatically reduced by using semi-insulating orsilicon-on-insulator type process technologies.

[0102] There is a continuous DC path that directly connects theterminals of each of the amplifiers 21, i.e. the respective input/outputterminals of each and all of the inverters 23 a, 23 b, but this path ischaracterised by having no stable DC operating point. This DCinstability is advantageous in relation to the regenerative action ofeach of the respective amplifiers 21 ₁-21 ₄ and their positive feedbackaction.

[0103] Transmission-lines 15 hereof can be routed around functionallogic blocks as closed-loops that are ‘tapped into’ to get ‘local’ docksignals. CMOS inverters can be used as ‘tap amplifiers’ in a capacitive‘stub’ to the transmission-line 15, which can be ‘resonated out’ byremoving an equivalent amount of ‘local’ capacitance from thetransmission-lines, say by local thinning of conductor traces (15 a/15b) as above. Capacitive ‘clock taps’ can be spread substantially evenlyalong a transmission-line 15 hereof having due regard as a matter ofdesign to their spacings, which, if less than the wavelength of theoscillating signal, will tend to slow the propagation of the EM wave andlower the characteristic impedance Zo of the transmission-line (15), butwill still result in good signal transmission characteristics.

[0104] Within functional logic blocks that are small relative to clocksignal wavelength, unterminated interconnects work adequately for localclocking with phase coherence, see FIG. 15. For clarity, the pairs ofconnections to the transmission-line 15 are shown slightly offset,though they would typically be opposite each other in practice.Alternative tap-off provisions include light bidirectional of passiveresistive, inductive or transmission-line nature, or unidirectional orinverting connections, including much as for what will now be describedfor interconnecting transmission-lines 15 themselves.

[0105] Plural oscillators and transmission-lines 15 can readily beoperatively connected or coupled together in an also inventive manner,including synchronising with each other both in terms of phase andfrequency provided that any nominal frequency mismatch is not too great.Resistive, capacitive, inductive or correct length directtransmission-line connections/couplings, or any combinations thereof,can make good bidirectional signal interconnections. Signal connectionor coupling between transmission-lines can also be achieved using knowncoupling techniques as used for microwave micro-strip circuits,generally involving sharing of magnetic and/or electrical flux betweenadjacent transmission lines. Unidirectional connections can also beadvantageous. Connectors and couplings hereof are capable of maintainingsynchronicity and coherency of plural transmission-line oscillatorsthroughout a large system, whether within ICs or between IC's say onprinted circuit boards (PCBs).

[0106] Connection/coupling of two or more transmission-lines andcross-connection rules are similar to Kirchoff's current law but basedon the energy going into a junction, i.e. a connection or coupling, ofany number of the transmission-lines being equal to the energy comingout of the same junction, i.e. there is no energy accumulation at thejunction. When the supply voltage V+ is constant, the rule is, of curse,precisely Kirchoff's current law. By way of a practical example, ifthere is a junction common to three transmission-lines, the simplest,but not the only, solution is that one of the transmission-lines hashalf the characteristic impedance of the other two transmission-lines.Where there are any even number of coupled transmission-lines, theirrespective characteristic impedances can all be equal. However, thereare an infinite number of combinations of impedances which will satisfyKirchoff's current law. The cross-connection rule, within atransmission-line, is the same as the rules for coupling two or moretransmission-lines described above.

[0107] There will be high quality differential signal waveforms Φ1 andΦ2, in terms of phase and amplitude, at all points around atransmission-line network 15 when the following criteria are met:

[0108] (i) the transmission-lines have substantially matching electricallengths

[0109] (ii) above Kirchoff-like power rules are satisfied

[0110] (iii) there is phase inversion.

[0111] There are, of course, an infinite number of coupled networkdesigns and supply voltages that will fulfil the above three criteria,such as for example: short sections of slow, low impedancetransmission-lines that are coupled to long fast, high impedancetransmission-lines; and one- and/or three-dimensional structures etc.However, for the best wave-shapes and lowest parasitic power losses, thephase velocities of the common-mode and the differential-mode, i.e. evenand odd modes, should be substantially the same. The same, orsubstantially the same, phase velocities can be designed into a systemby varying the capacitances of the transmission-lines.

[0112] The supply voltage V+ does not have to be constant throughout asystem, provided that above Kirchoff-like power/impedance relationshipsare maintained and result in an inherent voltage transformation systemthat, when combined with the inherent synchronous rectification of theinverters 23 a and 23 b, allows different parts of the system to operateat different supply voltages, and power to be passed bi-directionallybetween such different parts of the system.

[0113]FIG. 16 shows two substantially identical transmission-lineoscillators hereof that are operatively connected such that they aresubstantially self-synchronising with respect to frequency and phase.The transmission-lines 15 ₁ and 15 ₂ are shown ‘siamesed’ with thecommon part of their loop conductive traces meeting above Kirchoff-likepower/impedance rule by reason of its impedance being half theimpedances (20) of the remainders of the transmission-lines 15 ₁ and 15₂, because the common parts carry rotating wave energy of both of thetwo transmission-lines 15 ₁ and 15 ₂. As noted above, the originatingtrace length S of a transmission-line is one factor in determining thefrequency of oscillation so transmission-lines 15 ₁ and 15 ₂ using thesame medium and of substantially identical length S will havesubstantially the same frequency of oscillation F and will besubstantially phase coherent. In FIG. 10, respective EM waves willtravel and re-circulate in opposite directions around thetransmission-lines 15 ₁ and 15 ₂, see marked arrows 1L, 2L (or bothopposite), in a manner analogous to cog wheels. Such siamesingconnection of transmission-lines can readily be extended sequentially toany number of such ‘cogged’ transmission-line oscillators.

[0114]FIG. 17a shows another example of two substantially identicaltransmission-line oscillators with their transmission lines 15 ₁ and 15₂ operatively connected to be substantially self-synchronising infrequency and phase by direct connections at two discrete positions 40and 42. FIG. 17b shows such direct connections via passive elements 44,46 that could be resistive, capacitive or inductive or any viablecombination thereof. FIG. 17c shows such direct connections viaunidirectional means 48 that can be two inverters 50 ₁ and 50 ₂. Theunidirectional means 48 ensures that there is no coupling or signalreflection from one of the transmission-lines (15 ₂) back into the other(15 ₁), i.e. only the other way about. Directions of travel ofre-circulating EM waves are again indicated by arrows 1L, 2L that aresolid but arbitrary for transmission-line oscillator 15 ₁ and dashed for15 ₂ in accordance with expectations as to a ‘parallel’-coupled pair oftransmission-lines yielding contra-directional travelling waves. FIG. 18is a convenient simplified representation of the two self-synchronisedtransmission-line oscillators of FIG. 17a, and similar representationswill be used in following Figures.

[0115]FIG. 19a shows four self-synchronised transmission-lineoscillators 15 ₁-15 ₄ connected together basically as for FIGS. 17a-17c, but so as further to afford a central fifth effectivetransmission-line timing signal source of this invention affording are-circulatory travelling EM wave according to indicated EM wave lappingdirections 1L-4L of the four transmission-line oscillators 15 ₁-15 ₄. Asshown the central fifth transmission-line oscillator physicallycomprises parts of each of the other four, and has a lapping direction5L that is opposite to theirs, specifically clockwise forcounter-clockwise 1L-4L. It will be appreciated that this way ofconnecting transmission-line oscillators together can also be extendedto any desired number and any desired variety of overall pattern tocover any desired area.

[0116] An alternative is shown in FIG. 19b where the central fifthtransmission-line oscillator is not of re-circulating type, but isnonetheless useful and could be advantageous as to access to desiredphases of timing signals.

[0117]FIG. 20 shows two self-synchronising oscillators with theirtransmission-lines 15 ₁ and 15 ₂ not physically connected together,rather operatively coupled magnetically; for which purpose it can beadvantageous to use elongated transmission-lines to achieve more andbetter magnetic coupling. FIG. 21 shows another example of magneticallycoupled self-synchronising oscillators with transmission-lines 15 ₁ and15 ₂ generally as for FIG. 20, but with an coupling enhancingferromagnetic strip 52 operatively placed between adjacent parts to bemagnetically coupled.

[0118]FIG. 22 shows three self-synchronising oscillators with theirtransmission-lines 15 ₁, 15 ₂ and 15 ₃ magnetically coupled by a firstferrous strip 52 placed between transmission-lines 15 ₁ and 15 ₂ and asecond ferrous strip 54 placed between transmission-lines 15 ₂ and 15 ₃.As a source of oscillating signals, the transmission-line 15 ₂ does notneed any regenerative provisions 21 so long as enough energy foroscillation is magnetically coupled from the other transmission-lines 15₁ and 15 ₃ that are complete with provisions 21. It is consideredpractical for the transmission-line 15 ₂ to be longer and circumscribe alarger area but not to need or have regenerative provisions 21, nor across-over 19; and is then preferably an odd multiple (3S, 5S, 7S etc)of the length (S) or at least the electrical length of at least one ofthe transmission-lines 15 ₁ and 15 ₃. This, of course, has furtherimplications for self-synchronising frequency- and phase-locking ofoscillators (say as using transmission-lines 15 ₁ and 15 ₃), at aconsiderable spacing apart.

[0119] Further alternatives include use of a dielectric material (notillustrated) that spans over and/or under the portions of the conductivetraces to be electromagnetically coupled.

[0120] It is feasible and practical to synchronise transmission-lineoscillators operating at different frequencies. In FIG. 24,transmission-lines of two self-synchronising oscillators are ofdifferent electrical lengths. Specifically, using same transmission-linestructure/materials, first transmission-line 15 ₁ has a total conductivelength S for a fundamental oscillating frequency F=F1 and is operativelyconnected and synchronised to a second transmission-line 15 ₂ having atotal conductive length that is one third of that of the firsttransmission-line 15 ₁, i.e. S/3, thus an oscillating frequency of 3F.The dashed lines with arrows indicate the direction of rotation of theEM waves. Operative connection is as for FIGS. 17a-c, though any othertechnique could be used. Self-synchronising is due to above-mentionedpresence in the highly square first transmission-line signal of a strongthird harmonic (3F). Similar results are available for higher oddharmonics, i.e. at frequencies of 5F, 7F etc.

[0121] Preferred coupling between transmission-lines of oscillatorsoperating at such different odd harmonic related frequencies, isunidirectional so that the naturally lower frequency line (15 ₁) is notencouraged to try to synchronise to the naturally higher frequency line(15 ₂). Any number of transmission-line oscillators of differentodd-harmonically related frequencies can be coupled together andsynchronised as for FIG. 24.

[0122] Re-circulatory transmission-line oscillators hereof can be usedin and for the generation and distribution of reference, i.e. clock,timing signal(s) in and of a semiconductor integrated circuit (IC); andis also applicable to a printed-circuit-board (PCB), e.g. as serving tomount and interconnect circuitry that may include plural ICs, or indeed,any other suitable apparatus/system where timing reference signal(s)is/are required.

[0123] For ICs as such, simulations using the industry standard SPICEtechniques show potential for supplying clock signals of very highfrequencies indeed, up to several tens of GHz, depending upon the ICmanufacturing process employed and projections for their development.Generation and distribution can effectively be at, and service, allparts of an IC with predictable phases at and phase relationshipsbetween such parts, including as multiple clock signals that may havethe same or different frequencies. Moreover, principles of operation oftransmission-line oscillators hereof and their self-synchronisinginter-coupling extend or lead readily not only to reliable service oftiming signals to operational circuitry within any particular IC andbetween ICs, but further and it is believed also importantly andinventively to data transfer between ICs etc.

[0124] The entire transmission-line 15 structure and network involvingregenerative circuits 21 oscillates. The transmission-line 15 operatesunterminated, i.e. the transmission-line forms a closed-loop. Thecharacteristic impedance Zo of the transmission-line is low and only‘top-up’ energy is required to maintain oscillation.

[0125] Impedance between the two conductor traces 15 a, 15 b ispreferably evenly distributed, thus well balanced, which helps achievewell defined, differential signal waveforms (Φ1, Φ2). Coherentoscillation occurs when the signals Φ1, Φ2 on the transmission-line 15meet this 180°, or substantially a 180°, phase shift requirement for allinverting amplifiers 21 connected to the transmission-line 15 i.e. whenall the amplifiers 21 operate in a co-ordinated manner with known phaserelationship between all points along the transmission-line 15. Signalenergy is transmitted into the transmission-line 15 both inductively andcapacitively, i.e. magnetically and electrically, between the signalconductors 15 a, 15 b for the differential-mode, also between eachsignal conductor and the ground reference for the two individualcommon-mode (not present if the upper and lower ‘ground’ planes areabsent, nor for connections via unshielded twisted-pair cables).

[0126] CMOS inverters as non-linear, operative switching and amplifyingcircuit elements have low losses from cross-conduction current asnormally lossy transistor gate ‘input’ and drain ‘output’ capacitancesare absorbed into the characteristic impedance Zo of thetransmission-line 15, along with the transistor substrate capacitances,so power consumption is not subject to the usual ½.CV² formula.

[0127] It is quite often assumed that the power dissipation due tocapacitive charging and discharging of MOS transistor gates, forexample, is unavoidable. However, the self sustaining oscillating natureof the transmission-line 15 is able to ‘drive’ the transistor gateterminals with low power loss. This is due to the fact that the required‘drive’ energy is alternating between the electrostatic field, i.e. thecapacitive field of the MOS gate capacitances, and the magnetic field,i.e. the inductive field elements of the transmission-line 15.Therefore, the energy contained within the transmission-line 15 is notbeing completely dissipated, it is in fact being recycled. Energy savingapplies to all operatively connected transistor gates of thetransmission-line 15.

[0128] It is envisaged that low loss efficiency of transmission-lineoscillator hereof could well be used to ‘clock’ ICs for many previouslypopular logic systems that have since been overshadowed or abandoned asnon-viable options for reasons attributed to problems associated withclock skew, clock distribution, power consumption etc. Non-exhaustiveexamples of such logic arrangements include poly-phase logic and chargerecovery or adiabatic switching logic, such logic arrangements beingknown to those skilled in the art.

[0129]FIG. 24 shows a possible clock distribution network hereof asapplied to a monolithic IC 68 (not to scale, as is other Figureshereof). The IC 68 has a plural transmission-lines hereof shown as loops1L-13L, of which loops 1L-10L and 13L all have the same effectivelengths (say as for S above) and oscillate at a frequency F, and loops11L and 12L each have shorter loop lengths (say as for S/3 above) andoscillate at a frequency 3F. Loops 1L-8L and 11L-13L are fulltransmission-line oscillator complete with regenerative means, and loops9L and 10L arise as parts of four of the former transmission-lines,namely 1L, 3L, 4L and 5L; 4L, 5L, 6L and 8L respectively.

[0130] The transmission-line (15) of the loop 13L is elongated with along side close to the edge (i.e. scribe line) of the IC 68, so that itis possible to couple to another similarly set up separate monolithic ICfor inter-coupling by such as flip-chip technology for frequency andphase locking by such as magnetic coupling, as described above. Phaseand frequency locking of separate monolithic IC's can be very useful insuch as hybrid systems.

[0131]FIG. 25 indicates feasibility of a three-dimensional network ofinterconnected transmission line oscillators hereof for signaldistribution, specifically for a simple pyramidal arrangement, thoughany other structure could be serviced as desired, no matter how complexso long as interconnect rules hereof are met regarding electricallength, impedance matching, any phasing requirements for data transfer,etc.

[0132] ICs hereof can be designed to have whatever may be desired up tototal frequency and phase locking, also phase coherence, including forand between two or more self-sustaining transmission-line oscillatorsgreatly to facilitate synchronous control and operation of dataprocessing activities at and between all the various logic andprocessing blocks associated with such IC.

[0133]FIG. 26a shows an example of dual phase tap-off using a pair ofCMOS inverters 70 ₁ and 70 ₂ connected to the transmission-lineconductive traces 15 a and 15 b respectively to provide local clock toand/or to be distributed about a logic block 72 ₁. Whilst the logicblock 72 ₁ is shown as being ‘enclosed’ within the transmission-line 15alternatives include it being outside any area enclosed by thetransmission-line 15, as for the logic block 72 ₂ and its associatedinverters 70 ₃, 70 ₄, and/or it spanning the conductive traces 15 a, 15b of the transmission line 15. If desired, say for large logic blocks 72₁ and/or 72 ₂ plural pairs of inverters 70 can ‘tap’ into thetransmission-line 15, including for any desired phasing needed locallyin the logic block 72, see dashed line. Capability accurately to selectthe phase of the oscillating clock signals Φ1, Φ2 allows complexpipeline logic and poly-phase logic (see FIG. 29 below) to beoperatively designed and controlled.

[0134]FIG. 26b differs in that the logic blocks 71 ₁, 72 ₂ are replacedby respective processing elements 73 ₁, 73 ₂, though there could bemore, and for which one or more transmission-lines can be used to clockone or more of the processing elements. Two or a greater plurality ofprocessing elements can operate independently and/or together, i.e. inparallel to achieve very fast and powerful data processing ICs/systems.

[0135]FIG. 27a shows concentrically arranged transmission-lines 15 ₁-15₃ of progressively less physical lengths. However, each of the threetransmission-lines 15 ₁-15 ₃ can be made so that they all oscillate atthe same frequency, whether as a matter of structure or by respectivevelocities of the EM waves rotating around each of the shortertransmission-lines 15 ₂ and 15 ₃ being suitably retarded by increasingtheir inductance and/or capacitance per unit length. Moreover, thetransmission-lines 15 ₁-15 ₃ can optionally have one or more operativeconnections 70 and 72 that will serve to synchronise the threetransmission-lines 15 ₁-15 ₃. The advantages, apart from synchronicity,of having these connections 70, 72 are that the transmission-lines 15₁-15 ₃ will or can

[0136] (i) act as a single multi-filament transmission-line;

[0137] (ii) have smaller conductive traces (15 a, 15 b);

[0138] (iii) cover a larger clocking area;

[0139] (iv) produce lower skin effect losses; and

[0140] (v) produce lower crosstalk and coupling.

[0141]FIG. 28a shows a transmission-line having a cross-loop connectionbetween positions A, B, C and D, which comprises furthertransmission-line 15 c, 15 d that has, in this particular example, anelectrical length of 90° to match spacing of the positions A, B and C,D. Other cross-connection electrical length could be chosen, thenoperatively connected at correspondingly different spacings of thepositions A, B and C, D. Cross-loop connections allow further tap-offpositions within area enclosed by the transmission-line 15. Thetransmission-line part 15 d is shown connected in parallel, betweenpoints A and C, and part of the transmission-line 15 represented by line74. Likewise, the transmission-line part 15 c is shown connected inparallel, between points B and D, with part of the transmission-line 15represented by line 76. The transmission-line parts 15 c, 15 d, 74 and76 will be satisfactory if they each have an impedance that is half thatassociated with the remainder of the transmission-line 15, as above. Thetransmission-lines 15 and 15 c,d will have operatively connectedamplifiers 21. FIG. 28b shows the cross-loop connection 15 c,d and thepositions A, B, C and D set up relative to parts 78 and 80 of thetransmission-line 15, i.e. instead of parts 74 and 76, respectively; butwith Kirchoff-type rules applying again to result in parts 15 c, 15 d,78 and 80 each having an impedance of half that associated with theremainder of the transmission-line 15. Introduction of plural additionaltransmission-lines such as 15 c,d across a transmission-line 15 isfeasible as required.

[0142]FIG. 29a shows one way to produce four-phase clock signals.Effectively, a transmission-line 15 makes a double traverse of itssignal carrying boundary, shown as rectangular, and further repeatedtraverses could produce yet more phases. In the example shown, thepositions A1, A2, B1 and B2 will yield localised four-phase clocksignals, as will the positions C1, C2, D1, and D2. The repeated boundarytraverses will be with suitable mutual spacing/separation of thetransmission-line 15 to avoid inter-coupling. FIG. 29b shows idealisedfour-phase signal waveforms at points A1, A2, B1 and B2 and at C1, C2,D1 and D2.

[0143]FIG. 30 shows addition of an open-ended passive transmission-line(15 e, 15 f) connected to the closed-loop transmission-line 15 andhaving the characteristics, of having an electrical length of 180°, ofproducing no adverse effect at the tap point, since it acts as anopen-circuit oscillating stub. Amplifiers 21 will not be present alongthis open-ended line 15 e,f but inverters 23 could be far ends of eachof the traces 15 c and 15 d to reduce risk of spurious oscillations.Indeed, turned oscillation in such stubs 15 e,f can have usefulregenerative effects for the transmission-line 15 and thus serve forreinforcement and/or stability purposes.

[0144] Passive transmission-line connections with no particularrequirement for impedance matching can be used to connect oscillatingtransmission-lines of the same, or substantially the same, frequencytogether, at least provided that enough inter-connections areestablished between two systems, at connection positions with the samerelative phases in the inter-connected networks. Such connections canassist in synchronising high speed digital signals between IC's andsystems because non-clock signals (i.e. the IC/system data lines) willhave similar delay characteristics if they are incorporated into thesame routing (e.g. ribbon cable, twisted pair, transmission-line) as theclock connections, thus making data and clocking coherent betweendifferent systems.

[0145]FIG. 31 shows one example of coherent frequency and phaseoperation of two clock distribution networks of two monolithic ICs 68 ₁,68 ₂ each having a clock generation and distribution hereof and pairs ofinter-IC connections E, F and G, H. The two ICs concerned will operatecoherently, i.e. at the same frequency and with the same phaserelationships, where each of the connections is substantially of180-degrees electrical lengths, or a multiple satisfying 360°.n+180°where n is zero or an integer.

[0146] A single pair of inter-IC connections (E, F or G, H) will resultin frequency and phase ‘locking’ More than one pair of inter-ICconnections (E, F and G, H as shown) will result further in clock wavedirection or rotation locking.

[0147] Also shown in FIG. 31 is a first and second ‘stub’ connections 82and 83, though there could be more of either or each. The first stubconnection 82 has a total electrical length of 180° to assist instabilising operation. The second stub connection 83 is open-ended andalso of 180° electrical length and helpful for stabilisation. Such stubs82, 83 can be particularly useful for non-IC applications of theinvention where conductive trace definition may be less precise than forICs.

[0148] Impedance of the pairs of connections E, F and G, H andconnections 82, 83 can have any value since, in normal operation andonce these connections are energised, there will be no net power flowtherein for correct phasing thereof. It is, however, preferred that theimpedance of these connections E, F and G, H and 82, 83 is greater thanthat of oscillator transmission-lines 15 to which they are connected.These connections will support a standing EM wave rather than atravelling EM wave.

[0149] Such FIG. 31 inter-connections can be applied equally well tointra-IC, inter-IC, IC-to-PCB and/or any non-IC, i.e. PCB-to-PCB systemconnections.

[0150]FIG. 32a shows two interconnected monolithic IC's 68 ₁, 68 ₂ thatare phase and rotation locked and that further have a plurality ofbidirectional data latches 84 and links 86 between them inventivelyaffording separate data processing system connection to act as onecoherent structure as to phasing and further as to data transfer.Interconnection positions on the transmission-lines 15 concerned heresubstantially, a 180° phase difference between ends J, K of each lineinter-IC connection, though there is usually a tolerance of at least 1°.The plurality of inter-IC connections 86 can be of ‘twisted pair’ natureconnected between corresponding transmission-lines 15 of both IC's 68 ₁,68 ₂. Impedances of these inter-IC connections 86 are again preferablyhigher than that associated with the clock generation transmission-lines15.

[0151] It is not necessary for there to be equal numbers of clock/phaseand data connections. Moreover, the data and clock transmission mediums86 are of the same length and electrically matched, so both exhibit thesame propagation delays, which is advantageous. The nominal 180° phasedifference represents a half clock cycle, i.e. Tp, so a data pulsetransmitted from either IC to the other by the rising edge of the clockwaveform Φ1, will be received during, or just after, the rising edge ofthe clock waveform Φ2.

[0152]FIG. 32b shows the preferred inventive data latch 84 of FIG. 32aas a block. The data latch 84 is edge triggered by the differentialclock signals Φ1 and Φ2 for transmission (TX) and receiving (RX); andhas differential bidirectional input/output lines, data pulse controllines labelled TX Data and RX Data, and the clock signal waveforms Φ1,Φ2.

[0153] Techniques hereof greatly facilitate communicating data latches84 on different IC's 68 ₁, 68 ₂ being clocked with the same relativephasing. Moreover, FIG. 32a indicates that respective communicatingpairs of latches 84 are triggered on different phases, which results inwholly advantageous multi-phase data transfer that eliminates need forsimultaneous switching of the transmission-lines 86, thus results inreduction of ‘ground bounce’ and positive supply voltage dips.

[0154] In half duplex data transfer wherein, two data bits aretransferred, one each way, during each clock cycle. For data transfer(TX) from one IC to the other, and for local logic control where Φ1=1,Φ2=0 and logic 1=V+ and logic 0=GND, the corresponding latches 84 ateach IC both transmit a single bit of data for the period where Φ1=1,one data bit going from IC 68 ₁ to IC 68 ₂, and another data bit goingfrom IC 68 ₂ to IC 68 ₁ in each half cycle. The data signals pass eachother on the transmission-line 86, and do not interfere in the twistedpair nature of the transmission-line 86. The last received data signalis usable in this half cycle. When Φ1 and Φ2 are 180° from going highand low, respectively, data is received and the local logic states areΦ1=0, Φ2=1. The same latches 84 at each of the two IC's now both receivea single bit of data that was sent during the previous half cycle, whenΦ2=1.

[0155]FIG. 32c shows a circuit to implement the data latch 84.Transistors P1, N1, P5 and N5 are operatively arranged and controlled toproduce the differential output signals and are only active, i.e.switched ‘on’, when Φ1=1. Either P1 and N5 turn on for a positivedifferential output signal, or P5 and N1 turn on for a negativedifferential output signal. Transistors N4, P4, N8 and P8 areoperatively arranged and controlled to allow transistors P1, N1, P5 andNS to switch ‘on’ only when Φ1=1, i.e. during the transmit time.Transistors P2, N2, P6 and N6 are operatively arranged and controlled toswitch ‘off’ the output transistors P1, N1, P5 and N5 when Φ2=1, i.e.during the receive time.

[0156] Transistor N3 is operatively arranged and controlled by the TXData control signal for its associated differential bidirectional outputto go positive, i.e. V+, via transistors N4 and P1, when the TX Datacontrol signal is a logic 1. Transistor P3 is operatively arranged andcontrolled by the TX Data control signal for its associated differentialbidirectional output to go negative, i.e. GND, via transistors P4 andN1, when the TX Data control signal is a logic 0. The inverter I1 isoperatively arranged and controlled such that it produces the inverselogic state of the TX Data control signal.

[0157] Transistor N7 is operatively arranged and controlled by the TXData control signal for its associated differential bidirectional outputto go positive, via transistors N8 and P5, when the TX Data controlsignal is a logic 0. Transistor P7 is operatively arranged andcontrolled by the TX Data control signal for its associated differentialbidirectional output to go negative, via transistors P8 and N5, when theTX Data control signal is a logic 1.

[0158] Transistor N13 is operatively arranged and controlled toterminate the differential transmission-line 86 correctly during thereceipt (RX) of a data signal. Transistor T13 has an operative“on-resistance” that approximately equals the characteristic impedanceof the transmission-line 86.

[0159] Transistors N1-8 and P1-8 together with inverter I1 constitutethe transmit circuitry TX1 of the bidirectional latch 84.

[0160] Transistors N9 and N10 are operatively arranged and controlled to‘sample’ for a whole half cycle, onto capacitor C1, the differentialsignal during the receipt (RX) of a data signal. Transistors N11 and N12are operatively arranged and controlled to switch the stored chargesample of capacitor C1 onto the operatively arranged and controlleddifferential-to-single ended converter. This differential-to-singleended converter is made up by the operatively arranged and controlledinverters I2, I3 and capacitor C2. Inverter I3 and capacitor C3 areoperatively arranged as a voltage reference and inverter I2 isoperatively arranged and controlled such that it acts as a single endedlogic output buffer/amplifier for the sampled received (RX'd) datasignal.

[0161] Transistors N9-N11 and inverters I2 and I3 together withcapacitors C1 and C2 constitute the receiving circuitry RX1 of thebidirectional latch 84.

[0162] The following is a truth table that summarises the operation ofthe data latch 84 during the transmit (T) and receipt (RX) of datasignals. TX Data Φ1 Φ2 +ve Differential Output −ve Differential Output 00 1 Hi-Z (receiving) Hi-Z (receiving) 0 1 0 0 1 1 0 1 Hi-Z (receiving)Hi-Z (receiving) 1 1 0 1 0

[0163] It is noted that, for data link transmission-lines 86 with(360°.n+180°) electrical length there is an additional n cycle latency(delay), but subsequent data is received once per cycle. Furthermore,the phasing could be slightly different from different 180° for TX andRX circuitry within the I/O data latch 84 circuit so as to improve thetiming and therefore ‘hold times’ etc on the data latches 84 andtherefore compensate somewhat for switching delays.

[0164] The circuit diagram illustrated in FIG. 32c does not includeadditional waveshaping circuitry that may well be required in practice,but could be of well-known nature.

[0165] With clean differential waveshapes, package inductance problemsare minimised since GND and V+ package connection currents do not arisethrough the output switching action of the transmission-lines 86 since,the return currents are via the opposite signal of the differential pairand not through the supply pins. The matching of the package impedanceto the transmission-lines 86 is therefore easier.

[0166]FIG. 32d shows an intra-connected IC having plural unidirectionalreceive and transmit data latches, see 85 and 87. A first pair ofunidirectional transmit and receive latches 87 ₁, 85 ₁ are operativelyconnected to two different transmission-lines for operativelytransmitting data from one transmission-line to the other. The firstreceive latch 85 ₁ has a ‘delay correction through placement’ of 45°:where 45° represents the electrical length of respective clock signalconnections to the latches 87 ₁, 85 ₁.

[0167] Two pairs of unidirectional transmit/receive latches 85 ₂, 87 ₂and 85 ₃, 87 ₃ operate in the same manner as 87 ₁ and 85 ₁ except thattheir delay correction through placement is approximately 10°, whichrepresents the electrical length of their clock signal connections.

[0168]FIG. 32e shows unidirectional transmit and receive latches 85, 87able to transmit and receive two bits of data per clock cycle if theselatches 87, 85 respectively comprise two co-phase transmit or receivecircuits respectively TX1 and RX1, as opposed to each having a transmitand receive circuitry TX1 and RX1.

[0169]FIG. 33 illustrates digitally selectable shunt capacitors that areformed out of mosfet transistors.

[0170] Digitally selectable shunt capacitors illustrated in FIG. 33 canbe operatively connected to the transmission-line 15 and controlled forthe travelling EM wave to be delayed slightly, i.e. the frequency ofoscillation can be controlled. Such delays are useful for fine tuningthe frequency of a transmission-line(s). As shown, eight shuntcapacitors are implemented by means of mosfet transistors. The mosfetstransistors M1, M2, M5 and M6 are PMOS transistors and mosfettransistors M3, M4, M7 and M8 are NMOS transistors.

[0171] The mosfets M1, M3, M5 and M7 have their drain and sourceterminals connected to the ‘inner’ transmission-line conductor 15 a, forexample, and the mosfets M2, M4, M6 and M8 have their drain and sourceterminals connected to the ‘outer’ transmission-line conductor 15 b. Thesubstrate terminals of mosfets M1, M2, M5 and M6 are connected to thepositive supply rail V+ and the substrate terminals of mosfets M3, M4,M7 and M8 are connected to the negative supply rail GND.

[0172] The gate terminals of mosfets M1 and M2 are connected togetherand controlled by a control signal CS0 and the gate terminals of mosfetsM3 and M4 are connected together and controlled by the inverse ofcontrol signal CS0. Likewise, the gate terminals of mosfets M5 and M6are connected together and controlled by a control signal CS1 and thegate terminals of mosfets M7 and M8 are connected together andcontrolled by the inverse of control signal CS1.

[0173] The following truth table illustrates which mosfet shuntcapacitors (M1-M8) contribute capacitance, i.e. ‘Mosfets On’, to thetransmission-line 15. CS0 CS1 Mosfets ‘On’ Mosfets ‘Off’ 0 0 M1-M8 — 0 1M1-M4 M5-M8 1 0 M5-M8 M1-M4 1 1 — M1-M8

[0174] It is preferred that the respective sizes and numbers of shuntcapacitors connected to the ‘inner’ and ‘outer’ transmission-lineconductive traces 15 a, 15 b are the same, i.e. balanced. Whilst eightmosfet shunt capacitors M1-M8 are shown, any number of mosfet shuntcapacitors having suitable sizes, and hence capacitances, can be used,provided that the transmission-line 15 is balanced, as per FIG. 33.

[0175] There are other configurations for producing digitallycontrollable shunt capacitors that, may or may not be formed usingmosfet transistors. One known example, again using mosfets, could be theuse of binary weighted mosfet capacitors for example. Alternatives toMOS capacitors affording variable capacitance include varactors and P/Ndiodes for example.

[0176] It can be advantageous for the ‘capacitor arrays’ to bereplicated at regular intervals around the transmission-line(s) so as todistribute the impedance.

[0177]FIG. 34 shows how to route data and/or power across atransmission-line 15 and for altering its capacitive loading by way offormations 88 resembling railway sleepers deposited, preferably atregular intervals below the conductive traces 15 a, 15 b. Alternatively,formations such as 88 could be deposited above and/or below thetransmission-lines conductive traces 15 a, 15 b. As can be seen from thecross sectional view, the traces 15 a, 15 b are preferably on a metallayer that is isolated from the formation 88 e.g. by a silicon dioxide92 layer. These formations 88 have the effect of increasing thetransmission-lines capacitance and can therefore be used to alter thetransmission-line impedance thus the velocity of the travelling EM wave.These formations 88 can also be used to route data and/or power 99. Oneadvantage of routing data and/or power 99, as illustrated, is that sincethe clock signals Φ1, Φ2 on the transmission-line 15 are differential,these clock signals Φ1, Φ2 have no effect upon the routed data and/orpower signals.

[0178] The bi-directional switches (21) using inverters 23 a, 23 binherently act as synchronous rectifiers of the clock frequency as canbe deduced by the ohmic path from these inverters most negative supplyrail to GND and their most positive supply rail to V+. Therefore, theNMOS and PMOS transistors that constitute the back-to-back inverters 23a and 23 b (see FIG. 22b) will always be switched by an incident EM waveon the transmission-line 15 to a state where the two ‘on’ transistors(an NMOS and PMOS respectively) will connect the most negativetransmission-line conductive trace to the local GND supply for an NMOStransistor and the local V+ supply for a PMOS transistor. The twoNMOS/PMOS pairs of transistors alternate as the incident EM wave signalpolarity reverses for oscillation in the manner of bridge rectificationthat is synchronous and exemplifies the bi-directionality of theDC-AC-DC conversion mode involved. The transmission-line 15 is thus ableto extract and redirect power bi-directionally to supply power to thetransmission-line 15 when the local supply rail voltage is greater thanthe transmission-line voltage and to remove power when the local supplyrail voltage is less than the transmission-line voltage, and thetransmission-line 15 acts as a power conductor in this mode, seefollowing table: Inputs PMOS ‘on’ NMOS ‘on’ P/NMOS ‘off’ 15a = GND P1(15b connected to local V+) N2 (15a connected to local GND) N1, P2 15b =V+ 15a = V+ P2 (15a connected to local V+) N1 (15b connected to localGND) N2, P1 15b = GND

[0179] This power recycling is particularly appropriate to IC processtechnologies where the gate length is less than approximately 0.1microns when the parallel ‘on-resistance’ will be comparable to theseries DC resistance of the supply connections. Such synchronousrectification can act as the basis of power distribution in the absenceor impossibility of power supply routing to certain area's of an IC,particularly can be used for ‘charge pump’ circuitry, i.e. DC-to-DCpower conversion. There is also inherent capability for converting DC-toAC power conversion and visa versa. Alternatively, of course, known‘on-chip’ transformers could be employed.

[0180] The possibility is envisaged of achieving highest possibleoperating frequencies consistent with disconnectable switching of logiccircuitry, including as semiconductor fabrication technology is bound todevelop.

[0181] Indeed, transmission-line formations themselves should scale withIC process technology, thus smaller and faster transistor formationslead naturally to shorter and faster transmission-line oscillators foryet higher clock frequencies.

[0182] Other possibilities include maintaining low power consumption;regardless of applications, which could be as to any resonating ofcapacitive and inductive connections to a transmission-line, andspecifically use relative to such as shift registers or‘precharge’/‘evaluate’ logic.

[0183] Whilst there is evident advantage in not having to use externaltiming reference such as a quartz crystal, nor PLL techniques, there maybe situations and applications where this invention is applied inconjunction with such external timing crystals etc.

[0184] Whilst detailing herein has been within the context of currentlydominant CMOS technology for ICs, it will be appreciated by thoseskilled in the art that principles are involved that are also applicableto other semiconductor technologies, e.g. Silicon-Germanium (Si—Ge),Gallium-Arsenide (Ga—As) etc.

[0185] Finally, highly beneficial particular utility in overcoming theproblems associated with high frequency clocking, e.g. where F>1 GHz, noother applicability of combined timing signal generation anddistribution is to be excluded from intended scope hereof, say forsystems and apparatus to operate at frequencies less than 1 GHz.

1. Electronic circuitry comprising operational circuits of activeswitching nature requiring timing signals, and conductive means fordistributing said timing signals to the operational circuits, whereinthe timing signal distribution means includes a signal path exhibitingendless electromagnetic continuity affording signal phase inversion andhaving associated regenerative active means so as to serve as source ofsaid timing signals.
 2. Electronic circuitry according to claim 1,comprising a semiconductor integrated circuit having an active area withfeatures presenting the operational circuits and the timing signaldistribution means, including the signal path and its associatedregenerative active means together serving as the source of said timingsignals.
 3. Semiconductor integrated electronic circuit comprisingoperational circuitry of active switching nature requiring timingsignals, and conductive means for distributing said timing signals tothe operational circuitry, wherein part of the timing signaldistribution means is a signal path exhibiting endless electromagneticcontinuity affording signal phase inversion and having associatedregenerative active means so as to serve as source of said timingsignals.
 4. Electronic circuit/circuitry according to claim 1, whereinthe regenerative active means has switching action relative to twosupply voltage levels.
 5. Electronic circuit/circuitry according toclaim 4, wherein the regenerative active means has amplifying actionduring said switching.
 6. Electronic circuit/circuitry according toclaim 1, wherein the regenerative active means has inverting actionrelative to said timing signals in the signal path.
 7. Electroniccircuit/circuitry according to claim 1, wherein the regenerative activemean is of bidirectional nature so that said timing signal will havebipolar differential components available anywhere along the signal pathat 180° out-of-phase.
 8. Electronic circuit/circuitry according to claim7, wherein the signal path makes more than one loop in its endlesselectromagnetic continuity so that said timing signal is available inpoly-phase components including quadrature for one additional loop ofthe same sense.
 9. Electronic circuit/circuitry according to claim 1,wherein the regenerative active means is physically localised to oneposition along length of the signal path so that said timing signal willbe of standing wave nature.
 10. Electronic circuit/circuitry accordingto claim 9 with claim 7, wherein the bidirectional active means neverreaches fully “on” or fully “off” states so that said standing wavetiming signal is substantially sinusoidal.
 11. Electroniccircuit/circuitry according to claim 1, wherein the regenerative activemeans is physically distributed along length of the signal path so thatsaid timing signal will be of recirculating travelling wave nature. 12.Electronic circuit/circuitry according to claim 11, wherein theregenerative active means comprises plural inverting amplifiers spacedalong the signal path.
 13. Electronic circuit/circuitry according toclaim 12 with claim 7, wherein the bidirectional switching means reachesfully “on” and fully “off” states in relatively short parts of timetaken for said travelling wave timing signal to traverse the signal pathso that such timing signal is substantially rectangular.
 14. Electroniccircuit/circuitry according to claim 11, wherein the distributedregenerative active means has input/output terminals connected acrossthe signal path affording endless electromagnetic continuity of DCinterconnection of the terminals with no stable DC operating point. 15.Electronic pulse generator circuit comprising a signal path exhibitingendless electromagnetic continuity affording signal phase inversion insetting pulse duration within time of signal traversal of the signalpath which has associated regenerative active means setting relativelyshort pulse rise and fall times at ends of each said signal traversal.16. Travelling wave electronic oscillator circuit comprisingrecirculatory travelling wave propagation means affording a closedsignal path itself imposing phase inversion for each travelling wavecirculation, and regenerative active bidirectional switching andamplifying means operative during each circulation so that oppositevoltage excursions result for successive travelling wave circulations.17. Electronic circuit/circuitry according to claim 1, wherein thesignal path is of transmission-line nature and said timing signal is oftransverse electromagnetic wave form.
 18. Electronic circuit/circuitryaccording to claim 1, wherein the regenerative means serves to top uplow energy losses from low impedance of electromagnetically endless saidsignal path.
 19. Electronic circuit/circuitry according to claim 1,wherein the signal path is of transmission-line nature and includestransmission-line transformer means affording said phase inversion. 20.Electronic circuit/circuitry according to claim 1, wherein the signalpath is of transmission-line nature comprising spaced generally parallelconductive formations on a substrate with cross-over connection of theconductor formations affording single endless conductive length. 21.Electronic circuit/circuitry according to claim 20, wherein thetransmission-line signal path is a structure of co-planarmicrostrip/microstrip nature.
 22. Electronic circuit/circuitry accordingto claim 21, wherein the transmission-line structure comprises spacedconductive traces sandwiched by dielectric layers and affordingdifferential-mode said timing signals.
 23. Electronic circuit/circuitryaccording to claim 22, wherein the dielectric layers are sandwiched byconductive layers affording shielding and/or enabling common-mode saidtiming signals.
 24. Electronic circuit/circuitry according to claim 22,wherein capacitive and/or inductive reactance of the transmission-linesignal path is determined by particular geometry of the conductivetraces and their spacing along their lengths.
 25. Electroniccircuit/circuitry according to claim 24, wherein the geometry is locallyvaried as may be required to accommodate reactance of connections to thetraces.
 26. Electronic circuit/circuitry according to claim 19, whereinthe signal path has an electrical length of substantially 180-degreesand the regenerative means is of bidirectional inverting switching andamplifying nature.
 27. Electronic circuit/circuitry according to claim26, wherein the regenerative means comprises back-to-back inverters. 28.Electronic circuit/circuitry according to claim 27, wherein theinverters are P-channel and N-channel Mosfet circuits.
 29. Electroniccircuit/circuitry according to claim 28, wherein the inverters switchsequentially in one direction around the signal path and are connectedto supply voltage lines for passage thereto of energy received from nextinverter switching so as to reinforce recirculating traversal of thesignal path by said timing signal.
 30. Electronic circuit/circuitryaccording to claim 1, wherein the signal path has an cross-connectionalso active for said timing signals and of an electrical length ofsubstantially half that of the signal path.
 31. Electroniccircuit/circuitry according to claim 1, wherein the signal path hasextent affording physical adjacency to the operational circuits andclose electrical connectivity therefor directly to the signal path. 32.Electronic circuit/circuitry according to claim 31, comprisingelectrical connections to the signal path for the supply of the timingsignals to the operational circuits, whether of light bidirectionalnature through passive resistive or capacitive or inductive paths or ofunidirectional nature through diodes or inverters, or of transmissionline nature, or otherwise.
 33. Electronic circuit/circuitry according toclaim 32, wherein the connections are by way of capacitive stubs fromthe transmission-line signal path.
 34. Electronic circuit/circuitryaccording to claim 33, wherein the capacitive stubs are spaced evenlyalong the transmission-line signal path.
 35. Electroniccircuit/circuitry according to claim 32, wherein the connections are byway of Mosfet inverters.
 36. Electronic circuit/circuitry according toclaim 1, comprising more than one said signal path.
 37. Electroniccircuit/circuitry according to claim 36, wherein at least two saidsignal paths are intercoupled to operate synchronously by sharing ofmagnetic and/or electric fields.
 38. Electronic circuit/circuitryaccording to claim 36, wherein two said signal paths have a part that iscommon to both with an impedance substantially half that of remaindersof the two signal paths.
 39. Electronic circuit/circuitry according toclaim 36, wherein at least two said signal paths are interconnected tooperate synchronously.
 40. Electronic circuit/circuitry according toclaim 39, wherein self-synchronising interconnection between said signalpaths intended to operate at substantially the same frequency is viapassive circuit means affording light bidirectional coupling. 41.Electronic circuit/circuitry according to claim 40, whereinself-synchronising interconnection between said signal paths intended tooperate at different frequencies having odd harmonic relation is viainverter means poled against the higher frequency affecting the lowerfrequency.
 42. Electronic circuit/circuitry according to claim 39,wherein interconnected said signal paths have impedances to assuresubstantial match of energy into and out of interconnection concerned.43. Electronic circuit/circuitry according to claim 39, whereininterconnection or intercoupling is to both of spaced conductors of thesignal path at matching positions along electrical lengths of theirloops relative to means for imposing phase inversion on said signalstiming.
 44. Electronic circuit/circuitry according to claim 41, whereinplural said signal paths are interconnected directly at mutualelectrical lengths of matching multiples of 45-degrees.
 45. Electroniccircuit/circuitry according to claim 40, wherein the signal paths areone within another and have parameter differences to harmonise time oftraverse by their said timing signals, thus their fundamentalfrequencies.
 46. Electronic circuit/circuitry according to claim 44,wherein, considering operational circuits served as in an areacorresponding to a nominally rectangular grid array, signal pathscorrespond with areas along rows and columns of said rectangular gridthat alternate with intervening areas also serviceable for supplying thetiming signals.
 47. Electronic circuit/circuitry according to claim 36,wherein at least one said signal path is connected to another or to anarray thereof by way of at least one transmission-line connection havingan electrical length nominally of 180-degrees or an odd multiple so assubstantially to secure frequency end phase lock.
 48. Electroniccircuit/circuitry according to claim 47, wherein two saidtransmission-line connections serve substantially to secure desired lockof direction of signal path traversing by the respective timing signals.49. Electronic circuit/circuitry according to claim 11, wherein at leastone connection made to a said signal path is of short-circuit naturewith an electrical length of substantially 90-degrees.
 50. Electroniccircuit/circuitry according to claim 11, wherein at least one connectionmade to a said signal path is of open-circuit nature with an electricallength of substantially 180-degrees.
 51. Electronic circuitry comprisingat least two semiconductor integrated circuits (ICs) each in accordancewith claim 3 for similar said timing signals, and IC-inter-connectionbetween the signal paths of each of the ICs over an electrical lengthand at positions of the signal paths to coordinate frequency and phasecoherence of one of the ICs with the other of the ICs.
 52. Electroniccircuitry according to claim 51, wherein the IC inter-connection has anelectrical length substantially the same as that of the signal lengthpaths or an odd multiple thereof.
 53. Electronic circuitry according toclaim 51, wherein the interconnected said positions in one and the otherof the ICs have a phase difference corresponding to the electricallength of their said signal paths.
 54. Electronic circuitry according toclaim 51, wherein a second different said IC inter-connection servesfurther to prescribe directions of travelling said timing signals alongtheir said signal paths.
 55. Electronic circuitry according to claim 54,further comprising bidirectional data transfer means at each IC furtherco-ordinated with the coordinated timing signals.
 56. Electroniccircuitry according to claim 55, wherein the data transfer meanscomprises bidirectional data latches controlled by two-phasedifferential bipolar said coordinated timing signals so as each totransmit a data bit to the other during the same half cycle of thetiming signals and both to receive those data bits in the next halfcycle of the timing signals.
 57. Electronic circuitry according to claim56, comprising twisted pair said connections.